Method of making laminated furniture panels



Dec. 22, 1942 L. v. cAsTo 2,306,295

METHOD OF MAKING LAMINATED FURNITURE PANELS Filed May 4, 1939 INVENTOR. LLOYD 1/. 6457-0 ATTORNEYS I rials comprising the decorative finish.

Patented Dec. 22, 1942 OFFICE METHOD OF MAKING LAMINATED FURNI- TURE PANELS Lloyd V.Casto, Detroit, Mich.

Application May 4, 1939, Serial N0. 271,757

Claims. (Cl. 1542) provision of a novel method of deriving a panel structure having an attractive decorative finish which will not be marred under the foregoing stated conditions.

A further object of the present invention is the provision of laminated panel structures which are economical in construction, while being adaptable to many uses in the furniture industry and which are durable undervarious environments of use.

A still further object of the present invention is the provision of a novel method of firmly affixing thin sheet-metal to a base material to form a panel and which metal, when ultimately decorated, serves to protect both the material comprising a decorative finish on the panel and the material comprising the base thereof.

Other objects of the invention will become apparent from the following description, setting forth a preferred method of constructing the panel and a preferred form of panel structure. The essential features of the invention are set forth inthe claims appended hereto.

In the drawing, Fig. 1 is a diagrammatical cross-section of the various materials utilized in carrying out my invention, the materials being shown in laminated relationsh'p and exaggerated in form, and Fig. 2 is a perspective view of a furniture panel, preferably having a base formed of a fibrous material, such as wood.

Broadly, I incorporate in a panel structure a thin metal sheet, upon which the decorative finish is carried, and which metal sheet serves as a heat conductor to protect the coating mate- I have determined that a definite relation exists between the coemcient of conductivity of a lamination of sheet-metal used upon the top of a scorchable fibrous base, such as wood, and the baking temperatures of the coating materials comprising the finish applied to the sheet-metal as a decorative covering. I first determine the baking temperature of the coating materials and the heatmarring temperature. By thus predetermining the thickness of the metalsheet, the materials comprising the finish coatings upon the top of the metal sheet and the fibrous material comprising the basecan be protected against marring and charring, respectively, when burning matches,

v cigarettes or hot utensils are carelessly placed conductiv capacity of the sheet-metal by predetermining its thickness so that the sheet is of su-fiicient cross-section to prevent any localized part of the metal from rising to a finish thereon.

As an example, when a panel is built up with a wood base, and a previously decorated sheetmetal lamination is secured to the top thereof, by the use of a suitable cement or glue, and the decorative coating applied to this metal has a baking temperature of about 350 degrees Fahrenheit, the thickness of th metal sheet can be varied, dependent upon the kind of metal which forms the sheet. When a sheet of metal, having a high conductivity factor. is used, the thickness of the metal sheet can be considerably less than when sheet-metal having a low conductivity factor is used. Economically practical sheet-metals for my present purposes are aluminum or sheet steel, although commercial circumstances might be such that thin sheet copper could be used.

The heat conductivity factor of sheet aluminum at about 78 degrees centigrade is about .495, while that of steel, at the same temperature, is about .107. These factors are determined by establishing the quantities of calories, which will be transmitted per second through a plate of the metal one centimeter thick, across an area of one square centimeter when the temperature difference is one degree centi rade. Hence, aluminum at about '78 degrees centigiade is about four and one-half times greater in heat conductivity than sheet steel. Thus, when sheet aluminum is used, the thickness thereof could be four times less than thethickness of sheet steel to disburse or conduct away from a localized heated zone on the panel surface, the heat tending to accumulate, although I prefer to maintain a ratio between the thickness of aluminum and steel of three to one.

I have determined that sheet steel, having a thickness of .016 of an inch, has been found to have a sufiiciently high heat dispersion or heat conductivity capacity to conduct heat away from a heated localized zone upon the panel finish, thus preventing charring of the wood base to which the sheet metal is afiixed, while also preventing any marring or discoloration of the materials comprising the finish upon the sheet-metal surface. An aluminum sheet .005 of an inchhas been found to perform the same function.

a suitable adhesive which will withstand localized heat while the same is being dispersed, may comprise latex and casein mixed with a suitable solvent, and the top and ground coatings for decorating the metal sheet having suflicient- 1y high baking points 'or temperatures, may have modified alkyd resin bases.

The order of assembly of the laminations forming the panel structure, as well as the application of the materials thereto, is important, for I have encountered considerable diificulty in devising a practical method of firmly affixing the metal sheet to the base material throughout the undersurface of the metal sheet, after the metal sheet had been decorated. When a glue or adhesive which would adhere .to the fibrous base was used, such materials fail to adhere properly to the underside of the sheet metal, and when an adhesive, which would adhere properly to thesheet metal was used, such materials fail to adhere to the fibrous base. This difilculty was overcome by applying a coating of material to the underside of the metal sheet, which could be baked on and an adhesive, which would adhere firmly to this baked coating and to the base material, was then used.

In the present method, the underside of the sheet of metal I, after having been cleaned properly, has applied thereto a varnish coating 2 of such predetermined baking temperature that when the decorating coatings to the top side and baked, the underside coating 2 will not deteriorate and will firmly adhere to the surface of the metal sheet. In other words, the material used in making the coatings 2, 3 and 4 are such that the coatings may have substantially common baking temperatures, although the sequence of coating applications to the top and bottom surfaces of the sheet metal may be reversed by the selection of proper materials which, when baked at a required temperature,'

will not cause deterioration of the previously applied coating. Also, if desired, by effecting a preliminary drying of the first applied coating, be the same eitherthe decorative coating or the sheet metal adhesive coating, the baking of both coatings may be obtained in one bake.

The coating of adhesive 5 can be applied to the fibrous base material 6, or, if desired, may be applied to the metal sheet over the varnish coating 2, whereupon the finished metal sheet I may be applied to the base 6 with sufilcient pressure, by the use of. any convenient means,- to bring about intimate contact throughout the top surface of the base material 6 and the underside of the treated sheet-metal I. By finishing the sheet of metal I and treating the undersurface thereof in the manner hereinbefore described, the proper drying and setting of the adhesive or glue at low temperatures, even at a comparatively cold temperature, can be effected without causing warping of the base material 6.

I am aware that attempts have been made heretofore to produce scorch-proof panels by incorporating a metallic sheet in a plurality of phenol formaldehyde treated layers of wood veneer and paper which were first assembled and cured while under heat and pressure to form a composite slab. However, by my present panel structure and method of forming the same, considerable economy in the manufacture of the panel is obtained and there is no limitation upon the extent of decorative variation made available to the manufacturer nor is there any limitation 3 and 4 are applied in the selectionof the fibrous materials forming ll fact, any photographically 'reproducable design,

or simulation may be obtained by placing a transfer of the same upon the ground coat surface as indicated by the dot and dash lamination or layer I in Fig.-1.

The base material may comprise solid wood or plywood, cork, plaster board, any of the commercially known fibre boards or a built-up base of wooden members may form the base.

I claim:

1. The method of producing a decorated burnproof finish on a furniture panel, which comprises applying to an undecorated side of a thin sheet of metal having a sufficiently high heat conductivity factor to disperse heat away from a localized zone of concentrated heat, an adhesive material in the form of a varnish which has a baking temperature substantially equal to or in excess of 300 F., drying or baking the said adhesive before the decorative coating has been applied to said sheet, applying decorative coatings of finishing materials having baking temperatures which are in excess of any localized raised temperatures to which the decorative finish may be subjected, by the resting of lighted cigarettes, cigars, matches, heated utensils, and the like thereupon, subjecting the decorated sheet to a baking temperature which substantially is equal to or less than the baking temperature of the under coating material, and causing said baked sheet to adhere to a base structure formed of wood or other fibrous material by interposing an adhesive between the baked underside of the sheet and the base and by subsequently subjecting the sheet and the base to pressure.

2. The method of producing a burn-proof fin- I nish on a furniture panel formed of wood or fibrous material comprising the selecting of a thin sheet steel having a thickness of approximately not more than one sixty-fourth of an inch, applying a coating of baking varnish to the under side of the sheet having a baking temperature of not less than substantially 350 F., baking said coating, applying to the other side of said thin steel sheet a ground coating comprising a synthetic resinous finishing material having a baking temperature which is equal substantially to the baking temperature of the previously applied coating, drying saidlast applied coating, applying thereover a decorative transfer formed of material having a baking temperature corresponding substantially to the baking temperature of the synthetic resinous ground coating material, subjecting the decorated panel to heat to effect the baking of said last named coatings, and applying said decorated sheet to the base structure of a furniture panel by interposing a coating of ad hesive which will adhere to the surface of the baked under coating and to the surface of the wooden base material while applying pressure to the decorated sheet.

3. The method of producing a bum-proof finish on a furniture panel formed of wood or fibrous material comprising the selecting of a thin sheet of steel having a thickness of approximately not more than one sixty-fourth of an inch, applying a coating of baking varnish tothe under side of the sheet having a baking temperature of not less than substantially 350 F., drying said coating, applying to the other or top side of said thin 2,806,295 steel sheet a ground coating comprising a synthetic resinous finishing material having a baking temperature which is equal substantially to the baking temperature of the previously applied coating; drying said last applied coating, applying thereover a decorative transfer formed of material having a baking temperature corresponding substantially to the baking temperature of the synthetic resinous ground coating, subjecting the decorated panel to a baking temperature of not less than 350 F. to efiect the baking of said coatings, and applying said decorated sheet to the wooden base, structure of the furniture panel by interposing acoating of adhesive which will adhere to the surface of the baked under coating and to the surface of the base material while applying pressure to the decorated sheet.

4. The method of producing a decorative burn proof finish on a furniture top panel formed of wood or fibrous material comprising utilizing a metallic lamination of a substantially minimum thickness which will have a sufiiciently high heat conductivity factor to disperse heat away from a localized zone of heat incident to the presence of burning objects or heated utensils at a sufficiently rapid rate to prevent marring of a coating material thereon having a baking temperature of substantially not less than 350 F., applying a coating of varnish to the under side of the sheet having a baking temperature which is not less substantially than 350 F., drying said coating, applying a decorative coating of a synthetic resinous finishing material tothe top side of the sheet having a baking temperature which is not greater than the baking temperature of the coating on the underside of the sheet, baking said coating at a temperature of not less than 350 F., then applying said decorated sheet to a base panel by interposing a coating of adhesive material which will bond to the baked varnish coating on the underside of the metallic lamination and to the wooden base material while applying pressure to the assembly.

5. The method of producing a decorative burnproof finish on a furniture top panel formed of wood or fibrous material comprising utilizing a metallic lamination of sheet steel of substantially minimum thickness but which will be of such thickness as to have a sufficiently high heat conductivity factor to disperse heat away from a localized zone of heat incident to the presence of burning objects or heated utensils at a sumciently rapid rate to prevent marring of a synthetic resinous coating material thereon having a baking temperature of substantially not less than 350 Eh, applying a coating of varnish to the under side of the sheet having a baking temperature which is not less than said 350 F., baking said coating, applying a decorative synthetic resinous ground coating of a finishing material to the top side of the sheet having a baking temperature which is not greater than the baking temperature of the undercoating, applying a design transfer thereover having a baking temperature within said range, baking said coatings,

then applying said decorated sheet to a base panel of wood or fibrous material by interposing a coating of adhesive material which will bond to the baked varnish coating on the underside of the metallic lamination and to the base material while applying pressure to the assembly.

LLOYD V. CASTO. 

